Vatican City (AsiaNews) - Safeguarding the "unconditional respect" due to every human being from the moment of conception, since from that moment on there is no "change of nature," nor can there be any "continuum of moral value." This is the essential motivation of "Dignitas Personae," the document from the Vatican congregation for the doctrine of the faith, expressly approved by Benedict XVI and presented today, intended to "propose answers to some new questions of bioethics, which prompt expectation and perplexity in vast sectors of society."

The concrete questions, like fertility assistance techniques, the freezing of embryos, preimplantation diagnosis, gene therapy, human cloning, the therapeutic use of stem cells, attempts to create hybrids are all examined in the light of these principles, leading to moral judgments. These are often negative, even though the Church "looks to scientific research with optimism, hoping that many Christians may dedicate themselves to progress in medicine, and to witnessing to their faith in this area," and "intends to bring a word of encouragement and trust in a cultural perspective that sees science as a valuable service to the overall good of life, and to the dignity of each human being."

Addressed "to the faithful and to all of those who seek the truth," the instruction - 37 pages long - is divided into three parts: the first recalls certain anthropological, theological, and ethical elements of fundamental importance; the second confronts new problems concerning procreation; the third examines some new proposed therapies that involve the manipulation of embryos or of the human genetic patrimony.

The first part asserts two principles: that "the human being must be respected and treated as a person from the moment of conception, and for this reason, from that very moment his rights as a person must be recognized" (no. 4), and that "the origin of human life . . . has its authentic context in matrimony and the family, in which it is generated through an act that expresses the reciprocal love between man and woman. Procreation that is truly responsible toward the unborn child must be the fruit of matrimony" (no. 6). "No invasion of the field," comments Archbishop Rino Fisichella, president of the Pontifical Academy for Life. "The Church," he added, "does not intervene in the area proper to medical science as such, but calls all of those concerned to ethical and social responsibility in their work."

The second part of the instruction is dedicated to fertility assistance techniques. The principle is that "all techniques are licit which respect the right to life and the physical integrity of every human being," "the unity of matrimony, which involves reciprocal respect for the rights of the spouses to become fathers and mothers only through one another," and "the specifically human values of sexuality, which demand that the procreation of a human person should come about as the fruit of the conjugal act" (no. 12).

Therefore "those techniques are admissible which present themselves as an assistance of the conjugal act and its fecundity," and "those interventions are certainly licit that are aimed at removing the obstacles to natural fertility." The same is not true of "in vitro" fertilization, because this involves the elimination of embryos. In reality, this is accepted "because it is presupposed that the embryo does not deserve full respect, because it is in competition with a desire to be satisfied." But this "is utterly deplorable." But "in the face of the instrumentalization of the human being at the embryonic stage, it must be repeated that the love of God does not make any distinction between the unborn child still in the womb of his mother, and the baby, or the young person, or the adult, or the elderly person" (no. 16).

In vitro fertilization - but also preimplantation diagnosis, and some forms of genetic engineering - also present the risk of eugenics, or of the "selection" of characteristics - like sex - of a child. "Intra Cytoplasmic Sperm Injection (ICSI)"Is also "morally illicit," because "it is a variation of in vitro fertilization" (no. 17).

The document also rejects the freezing of embryos, because this is "incompatible with the respect due to human embryos: it presupposes their production in vitro; it exposes them to serious risks of death or of the damage off their physical integrity, in that a high percentage do not survive the procedure of freezing and thawing; it deprives them at least temporarily of maternal welcome and gestation; it puts them in a situation in which they are susceptible to further offense and manipulation" (no. 18).

As for the large number of embryos already frozen, the document recalls the appeal issued by John Paul II, "to the conscience of the leaders of the scientific world, and in a special way to doctors, that the production of human embryos may be stopped, keeping in mind that no morally licit outcome can be seen" for them.

"Embryo reduction" is also illicit, used to reduce the number of embryos or fetuses present in the mother's womb, through their "direct elimination," and which, from an ethical point of view, "is an intentional selective abortion" (no. 21). A similar consideration applies to preimplantation diagnosis, because this "is ordinarily followed by the elimination of embryos designated as 'suspected' of genetic or chromosomal defects, or belonging to the wrong sex, or having undesired qualities." Furthermore, this, "treating the human embryo as mere 'laboratory material', effects an alteration and discrimination concerning the very concept of human dignity . . . This discrimination is immoral, and thus it should be considered legally inadmissible" (no. 22).

Also "intrinsically illicit" is any form of human cloning, including for therapeutic reasons, because "creating embryos for the purpose of destroying them, even if this is with the intention of helping the sick, is entirely incompatible with human dignity, because it makes the existence of a human being, even at the embryonic stage, nothing more than an instrument to be used and destroyed. It is gravely immoral to sacrifice a human life for a therapeutic purpose" (no. 30).

Finally, stem cells. In this case as well, it is permissible to use "methods that do not cause grave harm to the subject from which the stem cells are removed" (no. 32). Yes, therefore, to "removal a) from the tissues of an adult organism; b) from umbilical cord blood, at the moment of childbirth; c) from the tissues of fetuses who have died of natural causes" (no. 32). But no to the techniques that involve the destruction of human life. "It should be noted, in any case, that many studies tend to show more positive results with adult stem cells than with embryonic stem cells."